Electromagnetic actuator for a circular knitting machine

ABSTRACT

AN IMPROVED ELECTROMAGNETIC ACTUATOR FOR THE JACKS OF A CIRCULAR KNITTING MACHINE EMPLOYS A LOW-MASS COIL AS THE MOVABLE ELEMENT IN PLACE OF A RELATIVELY MASSIVE CORE TO MINIMIZE INERTIA AND MAXIMIZE SWITCHING SPEED. THE COIL IS COUPLED TO A LOW-MASS PUSH ROD TO MOVE ONE OF A PLURALITY OF THE JACKS INTO KNITTING POSITION IN RESPONSE TO AN OUTPUT SIGNAL COUPLED TO THE COIL FROM A PATTERN CONTROL MECHANISM.

Feb. 23, 1971 H, GLA-UNSlNGER- 3,564,870

ELECTROMAGNETICCTUATOR FOR A CIRCULAR KNITTING MACHINE Filed June 19, 1969 5sheets-sneet 1 INVENTOR I Heinz GLAUNSI'GER 8% m0 ATTORNEY Feb. 23, 1971 H. GLAuNslNGER 3,564,870

ELECTROMAGNETIC ACTUATCR FOR A CIRCULAR KNITTING MACHINE Filed June 19, 1969 3 Sheets-Sheet 2 ATTORNEY Feb-23,1971 H.G| AuNs|NGER y 3,564,870

ELECTROMAGNETIC ACTUATOR FOR A CIRCULAR KNITTNG MACHINE v Filed June 19. 1969 3 Sheets-Sheet S INVENTOR ATTORNEY United States Patent O 3,564,870 ELECTROMAGNETIC ACTUATOR FOR A CIRCULAR KNITTING MACHINE Heinz Glaunsinger, 161 Zuckerbergstr.

7 Stuttgart, Germany Filed June 19, 1969, Ser. No. 834,724 Claims priority, application Germany, June 22, 1968, P 17 60 710.2 Int. Cl. D04b 15 78 U.S. Cl. 66-50 2 Claims ABSTRACT F THE DISCLOSURE An improved electromagnetic actuator for the jacks of a circular knitting machine employs a low-mass coil as the movable element in place of a relatively massive core to minimize inertia and maximize switching speed. The coil is coupled to a low-mass push rod to move one of a plurality of the jacks into knitting position in response to an output signal coupled to the coil from a pattern control mechanism.

BACKGROUND OF THE INVENTION Circular knitting machines of the type described, e.g., in U.S. Pat. No. 2,173,488 to W. S. Tandler employ a single pattern sheet to knit a patternedv fabric made up, e.g. of design gures of several different colors of stitches and a ground. The pattern sheet, which controls the entire operation of the machine is scannedby suitable photoelectric scanners that react differently to the different kinds of areas on the sheet. Each scanner controls, via an appropriate pattern control mechanism, a separate electromagnetic selector or actuator which in turn selects an appropriate one of a plurality of jacks moving sequentially past the actuator to advance the selected jack and its associated needle into knitting position.

lEach elecromagnetic actuator employed in this general type of machine is usually a solenoid-type electromagnet having a movable, spring-biased armature which drives the then-opposed jack into operative position when the surrounding coil is actuated by an output signal from the pattern control mechanism. While this construction is reliable, the maximum switching speed (and thus the speed of actuation of the jacks) is limited by the relatively high inertia of the solenoid-type electromagnet.

SUMMARY OF THE INVENTION To eliminate this drawback, an improved electromagnetic actuator for this type of circular knitting machine includes a relatively low-mass, spring-biased coil as the movable element thereof. The magnetic field of the actuator core is established in a direction perpendicular to the desired direction of motion of the coil. The coil which is electrically excited by the output of the pattern control mechanism, is magnetically coupled to the core for movement relative to the core in he desired direction whenever the coil is excited. The coil may be mechanically coupled to a push rod or other linkage so that the motion of the coil is transmitted to the selected jack for moving the latter into operative position.

BRIEF DESCRIPTION OF THE DRAWING The nature of the invention and its advantages will appear more fully from the following detailed description taken in conjunction with the appended drawing, in which:

FIG. l is an elevation View, partly in section of a pattern-controlled circular knitting machine employing a prior-art electromagnetic actuator of the solenoid type;

FIG. 2 is a plan view of a portion of the machine of FIG. 1;

3,564,870 Patented Feb. 23, 1971 FIG. 3 is a partial elevation view of the machine of FIG. l, illustrating a jack and needle in operative knitting position; and

FIG. 4 is an enlarged, fragmentary plan view, similar to a portion of FIG. 2 and partly in schematic form, of a circular knitting machine employing an electromagnetic actuator having a relatively low-mass coil as the movable element.

DETAILED DESCRIPTION Referring to the drawings, the apparatus shown in FIG. 1 includes a known type of circular knitting frame comprising a cylindrical needle bed 20 having vertical slots in its cylindrical surface, in which are mounted a series of needle 21 and associated operating jacks 22 lying in alignment therewith. The jacks rest upon a support 23 on which the bed is also supported and the bed is rotated by means of a girth gear 24 which encircles it and meshes with a pinion 25 on a vertical drive shaft 26.

The support 23 is provided with a track 27 dened by upright flanges 27a, 27b and receiving the lower ends of the jacks, and in the rotation of the bed, the lower ends of all of the jacks move along the track 27 to the point 28 at which the ange 2711 is broken away to provide an opening opposite which lies an electromechanical selecting device 30. This device may take various forms, but in the construction shown, it includes an electromagnet provided with an armature 31 to which is attached a rod 32 encircled by a spring 33, the spring bearing at one end against the under side of the armature and at the other against a fixed part of the device. The rod is provided with a head 34 which engages a fixed part of the device and limits the movement of the rod by the spring, and attached to the head is a vertical blade 3S. The construction is such that upon energization of the electromagnet, the armature is attracted against the acion of the spring and moves the blade 3S through the opening 28 to engage the jack which happens to lie opposite the opening at that moment. Any jack so engaged is shifted so that its lower end passes into a track 36 defined by flanges 36a, 36b, while the jacks, which have not been shifted, enter a track 37 defined by flange 36b and ange 36a. Within the track 36 is a cam hump 38, and as the jacks are carried along by the rotation of the cylinder, those jacks which have been shifted into the track 36 are raised by the cam to engage and elevate their associated needles so that the latter take part in the knitting operation. As the jacks move down, the cam, their needles are restored to inoperative position by an appropriate cam not shown.

The selector 30 thus functions to segregate the jacks and needles into two groups, those which are to become operative in the knitting of stitches of thread from a particular supply, and those which remain inoperative. The jacks of the second group progress through the track 37 to the point 39 at which the outer flange 38a of the track is broken away to provide an opening opposite which is a second selector 40. Immediately ahead of the point 39, the track 36 shifts inwardly and at an intermediate track 41 is formed. This track is defined in part by the ange 36b and in part by a flange 41a, and it contains a cam hump 42. At the point 39, the group of previously inoperative jacks is subdivided into two groups by the action of the selector 40, and the jacks which are to become operative are shifted into the track 41 where they ride up the cam hump so as to elevate their corresponding needles and cause them to take part in the knitting operation. When this action has been completed, the jacks continue along the track 41 to the point 43 where the tracks 36 and 41 merge, so that beyond this point, the jacks which have been raised by either cam 38 or cam 42 move together along a single track 44. Beyond the point 43, the

3 track 37 turns inward slightly to continue in alignment with the track 41 and it contains a cam 45 which raises the jacks so that they cause their associated needles to take part in the knitting. Beyond the cam 45, the tracks 37 and 44 merge and continue as track 27.

With the arrangement described, it will be apparent that as the jacks are moved successively into registry with the first selector 30, the latter may be operated to select the jacks of the needles which are to knit stitches of a particular thread, and the selector acts to segregate the jacks into two groups, those which are to be active, and all the remaining jacks. The jacks of the second group are then presented successively to the second selector where they are subdivided into two groups, the first of which contains the jacks which actuate the needles which are to knit stitches of the second thread. The remaining jacks, which have not been acted on by either of the selectors, are then all raised by the cam 45 and the needles of these jacks knit stitches of the third thread, which is the ground of the pattern.

The control of the selectors 30 and 40 for the purpose referred to is accomplished by means of a single pattern sheet, the details of the control mechanism being illustrated in FIG. 1. The mechanism includes a frame comprising upper and lower plates 46a, 4611, supported in any suitable way and provided with bearings for a vertical drive shaft 47 carrying a gear 48 meshing with a pinion 49 on the drive shaft 26. The shaft 47 is driven at the same rate of rotation as the needle bed 20, and it carries a drum 50 on which is mounted a pattern sheet 51 carrying a representation of the pattern to be reproduced in the fabric. The pattern is scanned by two scanning devices which are disposed in the same angular relation with reference to the drum, as the selectors in relation to the needle bed. As illustrated in FIG. 2, the selectors are approximately 120 apart and the scanning means have the same relation.

The scanners are of the same general construction and each includes a carriage 52 mounted on screws 53a, 53h, mounted for rotation in the plates 46a, 46h, the screws being of opposite pitch and driven in opposite directions. For this purpose, each screw is provided with a Worm gear 54 at its upper end, and the gears are engaged on opposite sides by worms 55 on a shaft 56 which extends through and is supported in bearings in a housing S7 mounted on top of the plate 46a. Within the housing, the shaft 56 is provided with a pair of bevel gears 58, 58h, which gears are held against movement lengthwise of the shaft but are loose thereon, the gears being in constant mesh with a bevel gear 59 on a vertical shaft 60 mounted y in suitable bearings in the top of the housing. The shaft 60 is driven from the shaft 47 by sprocket wheels 61, 62 on the respective shafts, and a chain 63.

The bevel gears 58, 58b are provided with clutch members on their opposed faces, and splined to the shaft 56 between the gears is a cooperating clutch member 64, which is illustrated as engaged with the clutch member of gear 58. The clutch member 64 is engaged by one arm of a bell crank pivoted in a bracket 66 depending from the plate 46a, and by rocking the bell crank, the clutch member 64 may be shifted to engage the clutch member of gear 58b. When the clutch member 64 is engaged with the cooperating clutch member of a gear, that gear is held against rotation relative to shaft 56 so that it drives the shaft and the screws 53a, 5317 in one direction, and when clutch member 64 is shifted the direction of rotation of the screws is reversed. The carriage 52 is provided with nuts 67 engaging the screws, and the carriage is raised or lowered, depending upon the direction in which the screws rotate.

Within each carriage 52 is a light source 68 which directs a beam through a passage 69 upon the Surface of the pattern sheet, and the beam is reflected from the pattern through a passage 70l to a photoelectric cell 71. The cells of the two carriages are in circuit through lines 72 with amplifiers 73a, 73h, respectively, and current is supplied to the amplifiers from a source through lines 74. The ampliers supply current through lines 75a, 7Sb to the selectors 30 and 40, respectively, and the electrical connections are such that amplified current is supplied to each of the selectors in accordance with the reaction of its associated photoelectric cell to the control areas on the pattern sheet.

The pattern sheet carries a repersentation of the pattern made up of different kinds, for example, contrasting colors, which, of course, need not be the same as those in the fabric, but must, however, be such as to make it possible to obtain different reactions from the cells. Thus, for example, the circular figure 76 in the pattern may be grey, the triangular figure 77 green, and the background 78 black. In that case, current will flow through the photoelectric cell of the scanner for the selector 30 when the beam of the scanner strikes a grey area, and current will ow through the cell of the scanner for selector 40 when the scanner beam strikes both grey and green areas. No current will tlow through either cell when their beams strike the black background. Accordingly, as the pattern rotates while the carriages move down, for example, current may be supplied to the selector 30 whenever the photoelectric cell of its scanner receives light reflected from the spot 76, and each time the electromagnet of the selector is energized, its blade moves inward to shift any jack in front of it. If the spot 76 is of substantial size, the electromagnet of the selector may remain energized while several jacks are passing in front of its blade, in which case the blade remains in its inner position and shifts the jacks inward by cam action. At the same time, the selector 40 is receiving energy throughout the period that the photoelectric cell of its scanner is receiving light reflected from FIGS. 76 and 77, but since certain of the jacks have previously been shifted out of cooperative relation with the selector 40 by the action of the first selector, selector 40 acts merely to shift the jacks of needles which are to take part in the knitting of the area 77 lying outside the area 76. Both selectors are idle while their scanners are scanning the background 78.

As the carriages 52 approach the lower end of their path of travel, they engage adjustment screws 79 mounted in levers 80 pivoted on brackets 81 extending upward from the lower plate 46h. Each lever is connected by a rod 82 to one arm of a bell crank 65, and when the levers are swung to thep roper extent, they swing the bell cranks and thereby shift the clutch members 64 so as to reverse the direction of rotation of screws 53a, 53b. The carriages then move upward until they strike the adjustment screws 83 in the arms of bell crank levers 65 and restore the clutch members 64 to their initial position, in which they connect gears 58a to their shafts 56 and drive the carriage down again. This automatic reversal of the carriages may be omitted if desired, in which event, the frame is stopped and the carriages restored manually to initial position when the sheet has been scanned along a helical track from top to bottom or vice versa.

The solenoid-type electromagnet construction shown in FIGS. 1-3, while reliable, is limited in its speed of operation by the inertia of the relatively high mass armature 31. In accordance with the invention, such drawback is eliminated, in the manner shown in FIG. 4, by substituting a low-inertia electromagnetic actuator `81 for each of the electromagnets 30 and 40 of FIGS. 1-3 (for simplicity, only the actuator 81 substituted for the electromagnet 30 is shown in FIG. 4).

The actuator 81, which may be similar in construction to the arrangement of U.S. Pat. 2,621,224 to D. E. Priest, includes a fixed non-magnetic housing, which contains a composite ferromagnetic core 83. The core 83 includes a center leg 84 and a pair of opposed outer legs 86 and 87 in mutually parallel relation 'and joined at respective first ends thereof as shown (the legs extend in the direction of actuation of the selected jack).

Respective second ends of the legs 86 and 87 are spaced from a second end of the leg 84 by air gaps 88 and 89. Like magnetic poles are established in each of the outer legs 86 and 87, and the opposite magnetic pole in the center leg 84, by conventional means, e.g., by forming the core out of suitable permanently m-agnetized material or by winding a suitable excitation coil around the core and exciting such coil with a steady voltage.

With this arrangement, a magnetic eld is established across each of the air gaps 88 and y89 in a direction perpendicular to the legs 84, 86, and 87 and parallel to the plane of the drawing.

A low-mass, schematically depicted coil 91 is supported in coaxial relation around and in spaced relation to the center leg 84 within the air gaps 88 and 89 by means of a support assembly which includes (a) a pair of blocks 92 and 93 aflixed to the housing; (b) la leaf spring 94 attached to the blocks 92 and 93; and (c) a T-shaped push rod 97, of negligible mass, having a crosspiece 98 insulatingly aixed to an adjacent end of the coil 91. The spring 94 is bent to bias the coil 91 in a manner identical to the spring 33 of FIG. 2. The mass of the coil 91 is arranged to be no more than 10% of the mass of the core 83.

An end 99 of the push rod 97 extends outwardly through an aperture in the housing in the direction of actuation of the jacks 22. The end 99 is equivalent, mechanically and functionally, to the blade 35 of FIG. 2. Moreover, the needle bed support 23 and the associated components shown in FIG. 4 are equivalent, mechanically and functionally, to the corresponding components of IFIG. 2 and have been given like reference numerals.

The coil 91 (FIG. 4) is electrically connected to the Iamplier output lines 75a. Thus, when an output signal appears on the lines 75a the interaction of the core magnetic elds in the air gaps 88 and 89 and the current in coil 91 (which will be perpendicular to the plane of the drawing) will yield a resultant component of force that moves the coil 91 and the associated push rod 97 forward against the bias of the spring 94 so that the thenopposed one of the jacks 22 is moved into the track 36 by the push rod end 99.

It will be appreciated that with this arrangement, the movement of the actuator 81, accomplished with a lowinertia coil, can result in a substantial increase in switching speed over the prior-art design.

What is claimed is:

1. In a circular knitting machine having a plurality of knitting elements movable serially past an electro-magnetic actuator wherein the actuator is operated by output signals by a scanned pattern control arrangement to move the then-opposed element in a iirst direction, and into knitting position, an improved construction for the electromagnetic actuator which comprises:

a ferromagnetic core;

means for inducing a magnetic ield through the core;

a coil having a signicantly lower mass than the core;

means for electrically coupling the coil to the output of the pattern control arrangement to excite the coil upon the occurrence of an output signal from said arrangement;

support means for magnetically coupling the coil to the core for movement in the rst direction when the coil is excited and for biasing the coil yagainst movement when the coil is not excited; and

means for mechanically transmitting the movement of the coil to the then-opposed element to move s aid element into knitting position.

2. Apparatus as defined in claim 1 in which the mass of the coil is no more than 10% of the mass of the core.

References Cited UNITED STATES PATENTS 2,173,488 9/1939 Tandler et al. 66--50 3,283,541 11/1966 De Cerjat 66-50 3,365,916 l/1968 Ribler et al. 66--50 WM. CARTER REYNOLDS, Primary Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,564 ,870 Dated February 23, 1971 'nz Glau in r Inventor(s) Hel ns ge It is certified that error appears in the above-identified pate and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 4 "Heinz Glaunsinger, 161 Zuckerbergstr. 7 Stuttgart, GermanI should read Heinz Glaunsinger, Stuttgart, Germany, assi JEo C. Terrot So hne, Stuttgart-Bad Cannstatt, Germany, a

Signed and sealed this 17th day of August 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, Attesting Officer Commissioner of Paten 

